[QUOTE=xilman;297217]They appear to be realists: "We're in this for decades. But it's not a charity. And we'll make money from the beginning."[/QUOTE]

One has to wonder why they don't just mine our moon. An effective NEO collector, and far easier to get to (and back from).

Delta-v, anyone?

[QUOTE=chalsall;297245]One has to wonder why they don't just mine our moon. An effective NEO collector, and far easier to get to (and back from).

Delta-v, anyone?[/QUOTE]It's primarily a matter of gravity. A number of NEOs are much easier to get to than the moon as long as you don't mind lengthy journey times. Robots aren't quite as upset by weightlessness and ionizing radiation as are humans.

[QUOTE=xilman;297277]It's primarily a matter of gravity. A number of NEOs are much easier to get to than the moon as long as you don't mind lengthy journey times. Robots aren't quite as upset by weightlessness and ionizing radiation as are humans.[/QUOTE]Are they closer than the moon? And on a somewhat related question, do you actually need to achieve "true" escape velocity to get to the moon, since it is in (a very large) Earth orbit? (Ditto for these NEOs?)

[QUOTE=Dubslow;297280]Are they closer than the moon?[/QUOTE]Yes and no. Most of the time most of them are further away. It is possible for some of them to come closer than the moon and on [i]very[/i] unusual occasions one does.
[QUOTE=Dubslow;297280]And on a somewhat related question, do you actually need to achieve "true" escape velocity to get to the moon, since it is in (a very large) Earth orbit? (Ditto for these NEOs?)[/QUOTE]What is "true" escape velocity? This is not a trick question. What are you "truly" escaping from?

Even your claim that " it [the moon] is in (a very large) Earth orbit" is open to examination. If you examine the Earth-Moon system from a heliocentric viewpoint it's clear that the system is very unusual indeed. The moon's orbit is always concave to the sun. No other satellite in the solar system behaves like this. It's rather more as if the Earth-Moon system is a co-orbiting double planet than primary-satellite pair.

[QUOTE=xilman;297285] The moon's orbit is always concave to the sun.[/QUOTE]

...:shock:

*cue furious Wikipediaing (that will have to wait for tomorrow)*

(Suddenly I can't wait even less for Classical Mech I next semester which includes Lagrangians...)

[QUOTE=xilman;297277]It's primarily a matter of gravity. A number of NEOs are much easier to get to than the moon as long as you don't mind lengthy journey times. Robots aren't quite as upset by weightlessness and ionizing radiation as are humans.[/QUOTE]
Yes, and assuming that the idea is to bring these minerals away from the asteroids and back to Earth, the return journey would require only minimal energy to remove the gold and platinum from the asteroid; whereas doing the same from the moon would be another story, the energy required to do that probably costing far more than would be gained from the mined minerals. Gravity again.

I have to say that if this is the primary direction that reaching out into space is going to take in the coming decades, then I'm bitterly disappointed. It's not that I disapprove of mining for minerals that are rare on Earth, but there are surely more pressing concerns which ultra-expensive space missions should be addressing, and considering that we don't have the capacity to organise numerous different space missions we really should be prioritising. I would think we should be concentrating on protecting our planet from the real threats to our own survival - and those same near-Earth asteroids themselves form one of those threats of course. The detailed observation program which already aims to discover potential Earth-impacting objects should be complemented by a clear program to deflect any identified future impactor, and this program should not have to be developed in the frantic atmosphere of an identified impact just a few years or less in the future.

[QUOTE=Brian-E;297298]I would think we should be concentrating on protecting our planet from the real threats to our own survival - and those same near-Earth asteroids themselves form one of those threats of course. The detailed observation program which already aims to discover potential Earth-impacting objects should be complemented by a clear program to deflect any identified future impactor, and this program should not have to be developed in the frantic atmosphere of an identified impact just a few years or less in the future.[/QUOTE]Perhaps the best strategy towards the goal of redirecting potential impactors is to have financial incentives for people to start getting vehicles out into space. If we wait for governments to organise it we could be waiting a very long time with budget problems etc. and never actually be able to protect ourselves. But instead, if we have private sector funds greedy for profits we could then later leverage the existing (profit making) vehicles and convert them for asteroid diversion duties.

IMO: privately funded profit making incentives >>> government funded public protection incentives.

[QUOTE=xilman;297277]It's primarily a matter of gravity. A number of NEOs are much easier to get to than the moon as long as you don't mind lengthy journey times.[/QUOTE]Yes indeed. As the company's site at [URL]http://www.planetaryresources.com/2012/04/asteroid-mining-plans-revealed-by-planetary-resources-inc/[/URL] points out:

[quote]. . .

Of the approximately 9,000 known NEAs, there are more than 1,500 that are energetically as easy to reach as the Moon. ...[/quote]- - -

[QUOTE=Dubslow;297280]Are they closer than the moon?[/QUOTE]They can require less fuel for a round trip even if they're farther away than the Moon, because of (a) their negligible gravity that a ship would have to fight landing and launching, (b) some of their orbit configurations will allow the object's own velocity and positions to help achieve a minimal-energy transfer flight, and, not to be forgotten, (c) in many cases the Moon itself can be used for a gravity assist on the way there or back!!

- - -

[QUOTE=Brian-E;297298]Yes, and assuming that the idea is to bring these minerals away from the asteroids and back to Earth, the return journey would require only minimal energy to remove the gold and platinum from the asteroid[/QUOTE]Something I've not yet seen discussed in articles about this company's announcement:

Suppose a ship brings back mucho tons of gold/platinum/other. What will happen to the market price of gold/platinum/other?

[quote=Brian-E]I have to say that if this is the primary direction that reaching out into space is going to take in the coming decades, then I'm bitterly disappointed. It's not that I disapprove of mining for minerals that are rare on Earth, but there are surely more pressing concerns which ultra-expensive space missions should be addressing, and considering that we don't have the capacity to organise numerous different space missions we really should be prioritising.[/quote]I wouldn't worry about that. Along the lines retina points out: commercial space-mining will help bring about technological improvements in space vehicles that will be applicable to NEO defense, and stimulate wealth that can be tapped to support other space missions.

Furthermore, I don't see how the existence of commercial space-mining would diminish the community of space enthusiasts interested in other space missions who have been lobbying, and will continue to lobby, for non-commercial projects.

[QUOTE]Suppose a ship brings back mucho tons of gold/platinum/other. What will happen to the market price of gold/platinum/other?[/QUOTE]
[url]http://www.coinweek.com/bullion-report/how-much-gold-is-there-in-the-world/[/url]

[QUOTE=Xyzzy;297359][url]http://www.coinweek.com/bullion-report/how-much-gold-is-there-in-the-world/[/url][/QUOTE]

I prefer to think of a large warehouse roughly the size of a soccer pitch, with an array of 50x100 1-meter square pallets, each stacked roughly 1.5m high with gold bricks, each pallet a bit over 32 tons. (Interestingly, that is a good fraction of the load capacity of a typical semi trailer.)

Even just piled chest-high like that, it would take a very sturdy reinforced concrete floor to support the load.

By way of comparison, the underground vault of the Federal Reserve Bank of New York, reputed to be the world's largest depository (and resting on Manhattan bedrock, the same which makes the area so good for building skyscrapers), holds roughly 5% of the aforementioned "mined in history" amount, at least now that the dastardly grand-theft-NY-Fed plot by the notorious [url=http://www.google.com/url?q=http://www.imdb.com/title/tt0112864/&sa=U&ei=kr-YT6fTG4KYiQL46cAJ&ved=0CBEQFjAA&usg=AFQjCNEUuJfvZXgld9Rn1OC2s8DfYFP7-g]Gruber gang[/url] has been thwarted.

[QUOTE=cheesehead;297358]
Suppose a ship brings back mucho tons of gold/platinum/other. What will happen to the market price of gold/platinum/other?[/QUOTE]
Nothing. I hope you (all) don't imagine that the actual prices of precious metals have anything to do with the supply and demand. Especially gold, platinum and silver. I have a much better opinion about you (all)... :smile: